Isoelectronic Definition

Isoelectronic refers to two atoms, ions, or molecules that have the same electronic structure and the same number of valence electrons. The term means "equal electric" or "equal charge". Isoelectronic chemical species typically display similar chemical properties. Atoms or ions with the same electronic configurations are said to be isoelectronic to each other or to have the same isoelectronicity.

Related Terms: Isoelectronicity, Valence-Isoelectronic

Isoelectronic Examples

Read More

Valence Electron Definition in Chemistry

By Anne Marie Helmenstine, Ph.D.

The K⁺ ion is isoelectronic with the Ca²⁺ ion. The carbon monoxide molecule (CO) is isoelectronic to nitrogen gas (N₂) and NO⁺. CH₂=C=O is isoelectronic to CH₂=N=N.

CH₃COCH₃ and CH₃N=NCH₃ are not isoelectronic. They have the same number of electrons, but different electron structures.

The amino acids cysteine, serine, tellurocysteine, and selenocysteine are isoelectronic, at least with respect to valence electrons.

More Examples of Isoelectronic Ions and Elements

Uses of Isoelectronicity

Isoelectronicity may be used to predict the properties and reactions of a species. It is used to identify hydrogen-like atoms, which have one valence electron and are thus isoelectronic to hydrogen. The concept may be applied to predict or identify unknown or rare compounds based on their electronic resemblance to known species.